go.uber.org/yarpc@v1.72.1/internal/iopool/copy.go (about)

     1  // Copyright (c) 2022 Uber Technologies, Inc.
     2  //
     3  // Permission is hereby granted, free of charge, to any person obtaining a copy
     4  // of this software and associated documentation files (the "Software"), to deal
     5  // in the Software without restriction, including without limitation the rights
     6  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     7  // copies of the Software, and to permit persons to whom the Software is
     8  // furnished to do so, subject to the following conditions:
     9  //
    10  // The above copyright notice and this permission notice shall be included in
    11  // all copies or substantial portions of the Software.
    12  //
    13  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    14  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    15  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    16  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    17  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    18  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    19  // THE SOFTWARE.
    20  
    21  package iopool
    22  
    23  import (
    24  	"io"
    25  	"sync"
    26  )
    27  
    28  type buffer struct {
    29  	b []byte
    30  }
    31  
    32  const _copyBufSize = 1024 * 32
    33  
    34  var _pool = sync.Pool{
    35  	New: func() interface{} {
    36  		return &buffer{make([]byte, _copyBufSize)}
    37  	},
    38  }
    39  
    40  // Copy copies bytes from the Reader to the Writer until the Reader is exhausted.
    41  func Copy(dst io.Writer, src io.Reader) (int64, error) {
    42  	// To avoid unnecessary memory allocations we maintain our own pool of
    43  	// buffers.
    44  	buf := _pool.Get().(*buffer)
    45  	written, err := io.CopyBuffer(dst, src, buf.b)
    46  	_pool.Put(buf)
    47  	return written, err
    48  }